An increasing interest in cancer diagnosis has led to an attempt to find reagents useful in the diagnosis of cancer by their reaction with components of urine to produce a colored precipitate. Since a variety of metabolites are excreted in human urine, it has been suggested that the amount of specific metabolites in a patient's urine will vary depending upon the disease state of the patient. It has been found that the distribution of nuclear magnetic resonance (NMR) signals of the urine of cancer patients are quite different from those of the urine of noncancer patients. Specifically, NMR signals in the range of 3.00 ppm to 3.09 ppm are commonly observed in the urine of cancer patients.
As disclosed in Korean Patent No. 21558, the specific NMR signals observed in the urine of cancer patients are related to the presence of phenolic metabolites, such as tyrosine. Korean Patent No. 21558 also discloses a reagent (i.e., Millon's reagent) for use as a cancer diagnosis agent which identifies the presence of tyrosine in urine by the formation of a colored precipitate.
However, the use of Millon's reagent in the urine test is highly disadvantageous because of the instability of the precipitate formed in the reaction. The reason for this instability is that the mercury ions in Millon's reagent have a high complex-forming capacity but a relatively low ionization tendency in comparison with other metal ions. Thus, it is easily interfered with by inorganic salts and aromatic organocompounds that are coexisting in the urine sample.
Accordingly, there is a need in the art for reagents which react with the specific components present in the urine of cancer patients, and which do not exhibit the disadvantages, such as instability of the colored precipitate, associated with Millon's reagent.